Rotorcrafts typically have means of evacuation and escape that can be used in a controlled ditching or in an underwater escape following submersion or capsize. Rotorcrafts operating over water and certified for ditching are required to have at least one emergency exit above the waterline in each side of the rotorcraft, meeting at least the dimensions of a Type IV exit if carrying 9 passengers or less (a rectangular opening of at least 483 mm wide by 660 mm high (19″ by 26″)), with corner radii not greater than one third the width of the exit, in the side of the fuselage with a step-up inside the rotorcraft of not more than 737 mm (29″), or a Type III exit if carrying 10 passengers or more (the opening must be at least 508 mm wide by 914 mm high (20″ by 36″)); and the exits need not be at floor level. This Type III or IV emergency exit is likely to be the main access door if its bottom is above the waterline. In a controlled ditching accident, reports have shown that the door could be operated by a crew member or by one of the passengers. In the event of an accident involving capsize or submersion, or the waterline is above the bottom of other emergency escape openings, evidence shows that passengers are most likely to use a push-out window to escape.
Windows can be considered emergency escape exits if they meet the aforementioned minimum size requirements for an emergency exit. An escape window is a window fitting a rounded rectangular aperture with a minimum acceptable size, for example, of 483 mm×660 mm (19″×26″) (depending on the number of passengers in a part 29 transport category rotorcraft) per current FAA airworthiness regulations. Regulatory requirements stipulate that the means of opening emergency exits and escape windows should be rapid, obvious and openable from inside and outside. However, sufficient force must be appliedy to ensure removal of the windows. Furthermore, emergency lighting systems should be automatically activated to illuminate push-out windows. Another safety concern relates to the high risk of disorientation following capsizing, making location and use of push-out windows difficult.
The majority of designs of emergency escape push-out windows include lanyards or beading that must be removed before the window can be pushed out. Pull-tabs are then located in many different positions. The most difficult action when operating a push-out escape window appears to be the removal of the beading around the window. Other existing art uses elastomeric beading compressed between an inner and outer frame that allows the window to be pushed in or out when sufficient force is applied at one of the corners.
It would therefore be desirable and advantageous to provide an escape push-out window assembly, in particular for a rotorcraft, which obviates the aforedescribed shortcomings and which can be dislodged from the rotorcraft with less applied force in an emergency, for example ditching the rotorcraft, while still complying with government regulatory requirements relating to the size of the window and operational safety.